Structural Engineering & Statics
where the load goes
Concept

Directional method — where it appears

The exact check on a fillet weld, made on the stresses resolved onto its throat. The normal and two shear components are combined by von Mises and compared with the weld metal's strength, which gives a capacity depending on the direction of the force — from the along-the-weld value to √1.5 times it across.

Named by 2 essays across one field — each of them below, with the objects they name alongside it.

A fillet weld is stronger across than along. Capacity of a 4 mm throat over 100 mm, against the angle between the weld's axis and the load. Loaded along its length it carries 116.83 kN; loaded across it, 143.09 kN. The ratio is 1.22, which is √3/√2 exactly, and it comes out of the failure criterion rather than out of a test.

The weld that is stronger across than along

The same fillet weld, the same size, the same steel, carries twenty-two per cent more when the load runs across it than along it. The factor is exactly the square root of three over the square root of two, and it comes out of the yield criterion rather than out of a test.

connections · Weld strength Force and capacity round a weld group, which do not vary together. Utilisation round the c shape group under 100 kN at 150 mm, walked from one end of the weld to the other, with the force scaled onto the same axis for comparison. The capacity is 1460 N/mm where the force runs along the weld and 1789 where it runs across it — √1.5 more — so the utilisation is not simply the force in different units. The worst point is at 47 degrees to the weld, where the capacity is 1612 N/mm, and the group carries 182 kN against the 165 the along-the-weld value would allow.

The weld that is stronger where it is pulled

A fillet weld pulled across its axis is √1.5 stronger than the same weld pulled along it. On a group under an eccentric load the direction of the pull varies from point to point, so the capacity does too — and the gain that follows is worth twenty per cent at one eccentricity and nothing at all at another.

connections · Weld strength

Named alongside it

The objects these essays reach for when they reach for this one.

Fillet weldShear stressYield criterionConnectionConnection designDetailingDuctilityEccentricityStress combinationThroatUtilisationVon mises

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